Air cleaners are needed for a variety of applications, for example to provide cleaning of engine intake air for internal combustion engines. A wide variety of types of air cleaner arrangements and filter materials are known.
One known filter material, is filter media configured in a z-arrangement. Z-filter media generally comprises a corrugated or fluted media sheet secured to a facing sheet. The media is arranged to form a set of longitudinal flutes or air flow channels on one side of the corrugated or fluted media, and another set of flow channels on an opposite side of the corrugated or fluted media. In operation, flutes of one set of flutes are designated as inlet flutes, in which individual inlet flutes are left open at an inlet end or side of the media, and are sealed, folded or otherwise closed at an outlet end or side of the media. Analogously, the flutes of a second set of flutes are generally designated as outlet flutes, are sealed, folded or otherwise closed at the inlet end or side of the filter, and are left open at the outlet end or side of the filter. In operation, air passes into one flow face of the air filter construction, by passage into the open inlet flutes at an upstream end of the element. The air cannot flow out of the closed ends of these inlet flutes, so it must pass through the filter media into the outlet flutes. The filtered air then passes outwardly from an exit end of the filter element, through the open ends of the outlet flutes.
A variety of z-filter constructions are known; including, for example, the ones described in U.S. Pat. Nos. 5,820,646; 5,792,247; 6,190,432; and, 6,350,291; PCT Publication WO 97/40918; U.S. provisional application 60/395,009 filed 10 Jul. 2002; and the PCT Application U.S. 03/02799 filed Jan. 31, 2003 and claiming priority from U.S. Provisional 60/395,009; the complete disclosures of all eight references above being incorporated herein by reference. These types of media (among others) can be used in arrangements of the types described herein.
Z-filter media has been characterized as useable in coiled configurations, see for example U.S. Pat. No. 6,350,291; or in stacks of sheets of z-filter media, see for example FIG. 26 of U.S. Pat. No. 5,820,646.